2010 Volume 53 Issue 3 Pages 244-256
The aim of this study was to evaluate short-term fluoride uptake of the tooth structure using a fluoride-containing material and the effect of thermocycling on dye penetration. The materials tested included two giomers, Beautifil® and Imperva Fluoro Bond® (Shofu, BF), Reactmer® and Reactmer Bond® (Shofu, RR), a resin composite, Clearfil® ST and Clearfil® Mega Bond® (Kuraray, CM), a resinmodified glass ionomer cement, Fuji II LC Capsule® and cavity conditioner (GC, F II), and a conventional glass ionomer cement, HY-Bond Glasionomer-F® (Shofu, HY). Identical cervical cavities (5mm wide×3mm long×3mm deep) were prepared on extracted bovine teeth. Each material was used according to the manufacturer's instructions to restore five cavities for each group. The surfaces of the specimens were coated with nail varnish except for the cavity margins. Group C (control) was stored in distilled water at 37℃ for 2 weeks. Group F was immersed in 1,000ppm NaF solution for 5 minutes everyday, and thermocycled for 2,500 cycles with a 30 dwell time each in a 4℃ and 60℃ water bath. Then, all specimens were immersed in 0.2% basic fuchsin dye for 3 days and sectioned longitudinally through the center of the restoration. The sections were examined for microleakage and the superficial enamel and dentin cavity walls were analyzed for fluoride uptake using an EPMA device. The microleakage scores were determined using the dye penetration distance ratio against the total distance of the cavity. The data was statistically analyzed by the Kruskal-Wallis test and Mann-Whitney U-test (p<0.05). With the exception of HY, there was no significant difference in the dye penetration distance ratio between group C and group F. The width of the fluoride zone in HY and F II was about 200μm and RR and BF was about 90μm and 40μm, respectively. There was no significant difference in the width of fluoride uptake between group C and group F. One condition of this study, immersion in NaF solution, did not influence the width of the fluoride uptake. There was no significant difference of the fluoride uptake distance at any of the point of the cavities between group C and group F; therefore, it was recognized that the fluoride uptake to the cavity wall was not affected by the ability of restorative fluoride recharge.
